First In Situ Observations of Gaseous Volcanic Plume Electrification

Nicoll, Keri; Airey, Martin; Cimarelli, C.; Bennett, Alec; Harrison, Giles; Gaudin, Damien; Aplin, Karen; Koh, Kuang Liang; Knuever, Marco; Marlton, Graeme

doi:10.1029/2019gl082211

Cited by 20 publications

(17 citation statements)

References 43 publications

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“…Volcanic lightning is the result of ash electrification in volcanic plumes. It has been observed at volcanoes all around the world, representing a large variety of magma compositions and eruptive styles (Mather & Harrison, 2006;McNutt & Williams, 2010;Nicoll et al, 2019). It is also associated with several geophysical signals that can be used for volcano monitoring from a safe distance and especially in unfavorable weather conditions (Behnke & McNutt, 2014).…”

Section: Introductionmentioning

confidence: 99%

Electrification of Experimental Volcanic Jets with Varying Water Content and Temperature

Stern

Cimarelli

Gaudin

et al. 2019

Geophysical Research Letters

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Volcanic lightning-a near ubiquitous feature of explosive volcanic eruptions-possesses great potential for the analysis of volcanic plume dynamics. To date, the lack of quantitative knowledge on the relationships between plume characteristics hinders efficient data analysis and application of the resulting parameterizations. We use a shock-tube apparatus for rapid decompression experiments to produce particleladen jets. We have systematically and independently varied the water content (0-27 wt%) and the temperature (25-320°C) of the particle-gas mixture. The addition of a few weight percent of water is sufficient to reduce the observed electrification by an order of magnitude. With increasing temperature, a larger number of smaller discharges are observed, with the overall amount of electrification staying similar. Changes in jet dynamics are proposed as the cause of the temperature-dependence, while multiple factors (including the higher conductivity of wet ash) can be seen responsible for the decreased electrification in wet experiments.Plain Language Summary Volcanic explosive eruptions are accompanied by lightning strikes generated from the volcanic dust cloud. Here we have experimentally studied the effects of atmospheric water and plume temperature on the frequency and intensity of the lightning strikes. The results will feed a model for the use of volcanic lightning strikes to estimate plume contents and intensity. Key Points:• Natural observations on the influence of temperature and water content on volcanic lightning have been modelled in laboratory experiments. • The magnitude of electrification and discharging in plumes decreases significantly with added water. • At higher temperatures a decrease in magnitude of individual discharges is observed, while the total neutralized charge stays similar.

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Section: Introductionmentioning

confidence: 99%

Electrification of Experimental Volcanic Jets with Varying Water Content and Temperature

Stern

Cimarelli

Gaudin

et al. 2019

Geophysical Research Letters

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“…UAS have also been used to make atmospheric electrical measurements through electric charge sensors on meteorological radiosondes. Such sensors are supporting a recent resurgence of interest in the electrification of volcanic plumes by enabling vertical transects of average space charge density measurements [Nicoll et al 2019]. These measurements represent a strong advance over previous estimates made from sparse groundbased atmospheric electric gradient measurements [e.g.…”

Section: Geophysicsmentioning

confidence: 89%

“…In volcanology, the use of kites, balloons and tethered helikites is less common [e.g. Belousov and Belousova 2004;Diaz et al 2015;Müller et al 2017;Nicoll et al 2019;Pieri et al 2013a], but can offer advantages in places where regulations restrict the deployment of free-flying UAS.…”

Section: Vehicle Typesmentioning

confidence: 99%

Volcanological applications of unoccupied aircraft systems (UAS): Developments, strategies, and future challenges

James

Carr²,

D'Arcy³

et al. 2020

Volcanica

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Unoccupied aircraft systems (UAS) are developing into fundamental tools for tackling the grand challenges in volcanology; here, we review the systems used and their diverse applications. UAS can typically provide image and topographic data at two orders of magnitude better spatial resolution than space-based remote sensing, and close-range observations at temporal resolutions down to those of video frame rates. Responsive deployments facilitate dense time-series measurements, unique opportunities for geophysical surveys, sample collection from hostile environments such as volcanic plumes and crater lakes, and emergency deployment of ground-based sensors (and robots) into hazardous regions. UAS have already been used to support hazard management and decisionmakers during eruptive crises. As technologies advance, increased system capabilities, autonomy, and availabilitysupported by more diverse and lighter-weight sensors-will offer unparalleled potential for hazard monitoring. UAS are expected to provide opportunities for pivotal advances in our understanding of complex physical and chemical volcanic processes. Non-technical SummaryUnoccupied aircraft systems (UAS) are developing into essential tools for understanding and monitoring volcanoes. UAS can typically provide much more detailed imagery and 3-D maps of the Earth's surface, and more frequently, than satellites are able to. They can also make measurements and collect samples for geochemical analysis from hazardous regions such as volcanic plumes and near active vents. Through being quick to deploy, they offer key advantages during initial stages of volcano unrest as well as throughout eruptions. Data from UAS have already been used to support hazard management and decision-makers during crises. In the future, UAS will become increasingly capable of flying longer and more complex missions, more autonomously and with more sophisticated sensors, and are likely to become key components of broader sensor networks for monitoring and research.

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“…Aplin et al (2014) provide evidence that the decay of radioactive elements in the magma may lead to "self-charging" of ash. Very recently, Nicoll et al (2019) deployed sensors into a plume at Stromboli, finding that the gas phase itself is charged.…”

Section: Plume Lightning and Proximal Dischargesmentioning

confidence: 99%

Charge injection into the atmosphere by explosive volcanic eruptions through triboelectrification and fragmentation charging

Harper,

Cimarelli,

Cigala

et al. 2021

Preprint

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Volcanic eruptions are associated with a wide range of electrostatic effects. Increasing evidence suggests that high-altitude discharges (lightning) in maturing plumes are driven by electrification processes that require the formation of ice (analogous to processes underpinning meteorological thunderstorms). However, electrical discharges are also common at or near the volcanic vent. A number of "ice-free" electrification mechanisms have been proposed to account for this activity: fractocharging, triboelectric charging, radioactive charging, and charging through induction. Yet, the degree to which each mechanism contributes to a jet's total electrification and how electrification in the gas-thrust region influences electrostatic processes aloft remains poorly constrained. Here, we use a shock-tube to simulate overpressured volcanic jets capable of producing spark discharges in the absence of ice. These discharges may be representative of the continual radio frequency (CRF) emissions observed at a number of eruptions. Using a suite of electrostatic sensors, we demonstrate the presence of size-dependent bipolar charging (SDBC) in a discharge-bearing flow for the first time. SDBC has been readily associated with triboelectric charging in other contexts and provides direct evidence that contact and frictional electrification play significant roles in electrostatic processes in the vent and near-vent regions of an eruption. Additionally, we find that particles leaving the region where discharges occur remain moderately electrified. This degree of electrification may be sufficient to drive near-vent lightning higher in the column. Thus, near-vent discharges may be underpinned by the same electrification mechanisms driving CRF, albeit involving greater degrees of charge separation.

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First In Situ Observations of Gaseous Volcanic Plume Electrification

Cited by 20 publications

References 43 publications

Electrification of Experimental Volcanic Jets with Varying Water Content and Temperature

Electrification of Experimental Volcanic Jets with Varying Water Content and Temperature

Volcanological applications of unoccupied aircraft systems (UAS): Developments, strategies, and future challenges

Charge injection into the atmosphere by explosive volcanic eruptions through triboelectrification and fragmentation charging

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